Patent attributes
A planetary roller transmission device has a rotatable input shaft and an output shaft on the same axis, a plurality of planetary rollers which are rollable around the outer periphery of a sun roller provided on the input shaft, an output ring which is provided integrally with the output shaft, inside which the planetary roller roll, and a shift ring which is provided to be movable in only along the axis and with which the planetary roller internally and rollably contacts. The position at which the sun roller contacts the planetary rollers by pressing the planetary rollers in an outer direction is located between a first position at which the output ring contacts the planetary roller, and a second position at which the shift ring contacts the planetary roller. The planetary roller transmission device also has an axial direction pressing member which moves along the axis due to a centrifugal force caused by the rotation of the input shaft.